Soft iron rather than steel is used for the core of an electromagnet because soft iron
Correct answer: B. loses its magnetism quickly when the current is switched off
- A. is cheaper
- B. loses its magnetism quickly when the current is switched off
- C. retains its magnetism permanently
- D. conducts electricity better
Explanation
An electromagnet must be able to be switched off, which requires a core of low retentivity, and soft iron is easily magnetised and just as easily demagnetised. Steel retains magnetism and is therefore used for permanent magnets instead. This difference in hysteresis behaviour is the whole basis of choosing between them.
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About Magnetic Flux Density
Magnetic flux density measures the magnetic force acting on a current carrying conductor or moving charge in a magnetic field. Work includes the relations B equals F divided by IL and F equals qvB, the tesla as its SI unit, field direction and the distinction between flux density and magnetic flux.
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